1. Technical Field
The disclosed embodiments relate in general to an apparatus for generating a laser, and more particularly to an apparatus for generating a short-pulse laser using a temporally modulated sideband gain.
2. Description of the Related Art
FIG. 1 shows a diagram of a drilling depth produced by a conventional nanosecond laser. Compared to a picosecond laser, a nanosecond laser likely causes rough burrs and renders less satisfactory laser stripping quality.
In the prior art, a picosecond laser employs techniques including gain-switched diode, diode-pumped solid-state (DPSS) laser microchip, semiconductor saturable absorber mirror (SESAM) passively mode locked, and direct diode. Among the above, the gain switched diode is prone to producing a second peak pulse tail, as shown in FIG. 2. This kind of seed has quite low pulse energy of only several pico-joules (pj) and may easily affect and thus amplify the picosecond pulse to a nanosecond scale. As a result, signal amplification is made difficult to lead to increased laser costs. Further, a shift in a central wavelength is easily affected by an ambient environment, such that a temperature of a seed source of a laser diode likely drifts to bring about an unstable laser output. In the direct diode technique of the prior art, although the direct diode can be readily combined with an optical fiber laser and has controllable optical efficiency and temperature, a short-pulse circuit driver is nevertheless extremely costly. Further, a market-available product that outputs a shortest pulse width of approximately 600 picoseconds needs to operate with a driver circuit to generate an optical pulse. In the prior art, the DPPS laser microchip is implemented by a microchip cooperating with a DPPS laser crystal. However, a pulse width produced by the DPPS laser microchip is slightly too large at approximately above 500 picoseconds.